Heat exchanger



Patented Got. 25, 1932 j" UNi' rs s'rarss PATENT OFFICE V CHAELES F. BEBAN, OF TUCKAHOE, NEW YORK, ASSIGNOR TOCELANESE CORPORATION OF AMERICA, A CORPORATION OF DELAWARE HEAT EXCHANGER Application filed April 21,

I Thisinventionrelates to heat exchangers and. relates more-particularly to heat eX- changers for the heating'or cooling of fluids which are miscible 'or react chemically with the heating or cooling fluid.

An object oi my invention is to provide a heat exchanger wherein an inert liquid surrounds the joints through which the cooling or heating fluid is liable to seep into the fluid that is being cooled or heated. Other objects of this invention will appear from the following detailed description.

In thecondensi'n'g of vapors of liquids that react chemically with water, it has not been considered feasible toemploy a straight tube and plate type of condenser, since if the cool ing water seeps throughthe joints between the tubes and plate and then comes into contact with the liquid being condensedfdisastrous results may follow. Therefore for con-' densing such substances, coil type of condensers are employed. However to attain a large cooling area, such coil condensers must be quite large and are bulky since coils of large diameter are required. Moreover tubes in excess of certain diameter cannot be bent to a radius which is at least several times the diameter of the tube without creating fissures in the material.

A straight tube and plate type or condenser can be developed to a much more compact design. Furthermore the tubes do not have to be subjected to any bending, which operation creates differences in wall thicknesses of the tubes and thus shortening their lit Moreover materials can be used for the straight condenser tubes that cannot be bent easily. However with a standard design of straight tube and plate condenser, contamination of the condensate by the cooling medium can occur through leakages of 'the cooling medium through the openings of th lower tube plate into which the condenser tubes are expanded.

I have found that it a sealing liquid, which is preferably immiscible and non-reactant with both the cooling fluid and the fluid being cooled is caused to surround the joints where the tubes join the fluid. if leaks, fissures or cracks should develop in such oints,

1931. Seria1No.531,672.

the sealing fluid willseep through and serve as a warning of the presence of such fissures or leaks. i

For illustration of one embodiment of my invention, but without being limited thereto, reference is had to the accompanying drawing wherein,

Figure 1 is a front elevation, partly in section, of a heat exchanger embodying my invention, and

Figure 2 is a detailed enlarged view show-. ing the assembly of the lower part of the heat exchanger. i

.While this invention is of general application and is applicable to heat exchangers of all kinds wherein a fluid is to be heated or cooled, it will be. desc'ribedas a condenser for the condensing of vapors of acetic anhydride or other material that reacts chemicallywith water,- withthe use of water as a cooling fluid.

The condenser consists of an outer shell 1', providedwith cut away portions 2 at its lowon end, which're'sts on the tube'plate 3. The shell 1 is provided with the inlet a and outlet 5 for water or other cooling liquid, and has harness to cause thecooling water to take a; circuitous coursetor greater cooling efliclency. V i The vapor inlet header 7 has the cooling tubes 8 attached thereto, the lower ends ot which tubes are secured to or expandedinto the tube plate 3. The 'dishbottom' 9 is provided to collect the condensate'fromthe tubes 8. An upstanding collar or shell 10 surrounds and is spaced from the lower end of the shell 1.

' The flange 11 of the bottom 9, the tube plate 3 and the shell 10 are firmly held together by means of gaskets and bolts as is shown in Figure 2 to provide tight joints.

In accordance with this invention a heavy liquid A, which is preferably immiscible and non-reactant with both the material being condensed and the. cooling liquid, is inserted in the space between the upstanding collar or shell 10 and the shell 1 of the condenser, and this liquid flows through the slits or notches 2 to surround the oints between the tubes-8 and the-plate 2. While I prefer to use mercury as the sealing liquid, any other liquid that has a higher specific gravity than the cooling liquid and the liquid being condensed may be employed, .such as low melting alleys and amalgams, particularly when hi her temperatures prevail.

t will be understood that the outer shell 10 is of suificient height to contain a column of the sealing liquid A which balances the hydrostatic pressure of the column of the water or other cooling liquid contained within the shell 1.

A loose ring shaped cover 12 is provided which fits over the shell 10 to protect the sealing liquid A from dirt and the like. The condensate outlet is indicated at 13. A pet cock 14 permits sampling of the liquid acemulating in the lower part of the bottom 9'. The vapor to be condensed enters by the inlet 15.

In operation, the vapors of acetic anhydride or any other vapors to be condensed enter by 15 and pass through the tubes 8 where they are condensed, the condensate overflowing through pipe 13. Cooling water or other liquid enters by pipe 4 and rises through the shell 1 and overflows by pipe 5. The merany or other sealing liquid A covers the joint between the tubes 8 and plate 3, and is resent in the annular space between the shells 1 and 10 to such a height as to balance the pressure of water within the shell 1.

Should aleak develop in the joints between the tube 8 and theplate 3, the mercury or other sealing liquid will seep through and accumulate in the lower end of the bottom 9. By periodically opening the pet cock 14, an obsBrver can notice if any mercury or other sealing liquid discharges therethrough. If it does; this serves as a warning of leakage and that repair is necessary. Because of the seal of mercury and the like, the coolin water is not permitted to seep through a leafi between-the tubes and plate, thus avoiding dangerous results. I By raising the annular cover 12, the level of the sealing medium can be Checked at any time.

For cleaning the condenser tubes 8, shell 1 canbe removed conveniently without dismantling the condenser proper, since this shell is not fastened to the rest of the apparatus. It is rarely necessary to clean the inner surfaces oi the tubes 8, but if necessary the upper head 7Tof the condenser may be dismantled quite readily to permit access to the interior of such tubes.

It is to be understood that the foregoing detailed description is given merely by way of illustration and that many variations may be inade therein without departing from the spirit'of my invention. 7

Having described my invention, desire to secure by Letters Patent is: 1'. Ina heat-exdianger, the combination of a shell having an inlet and outlet for a coolwhat I ing liquid, tubes within said shell for the passage of fluid to be cooled, a tube plate upon which said shell rests and to which the lower ends of the tubes are joined, another shell surrounding the first named shell and spaced therefrom to form an annular space, and a sealing medium in said annular space and covering the tube plate.

2. In a heat exchanger, the combination of a shell having an inlet and outlet for a cooling liquid, tubes within said shell for the passage of fluid to be cooled, a tube plate upon which said shell rests and to which the lower ends of the tubes are joined, a chamber below said tube plate adapted to receive the discharge from said tubes, a cock attached to said chamber, another shell surrounding the first named shell and spaced therefrom to form an annular space, and a sealing medium in said annular space and covering said tube plate.

3. In a heat exchanger com rising an inlet header, an outlet header and tubes joining said headers, the combination of a shell surrounding said tubes and resting on one of said headers, and another shell attached to said header and surrounding at least the lower part of said first named shell and spaced therefrom to form an annular space for a sealing liquid, whereby the first named shell may be readily removed to permit access to said tubes. V

In testimony whereof, I have hereunto subscribed my name.

CHARLES F. BERAN. 

